Design, Manufacture, and Spin Test of High Contact Ratio Helicopter Transmission Utilizing Self-Aligning Bearingless Planetary (SABP)

Abstract : The objective of the subject program was to conduct research and development work on helicopter type transmissions to reduce propulsion system weight and to reduce airborne and structureborne noise and vibrations. The approach taken was to utilize precision high contact ratio helical gears in conjunction with a new concept of power transmission called the Self-Aligning Bearingless Planetary (SABP). The results accomplished under this contract include the design, manufacturing, and no-load spin testing of two prototype helicopter transmissions. Based on the results achieved to date, the subject high speed, high contact ratio SABP transmission appears to be significantly lighter and quieter than contemporary helicopter transmissions. Additional work activities are recommended to further develop and demonstrate this new transmission as a potential drive for Future Advanced Rotorcraft. It should also be noted that the concept of the SABP is applicable not only to high ratio helicopter type transmissions but also to other rotorcraft and aircraft propulsion systems.